The present invention relates generally to axial flow combine harvesters and, more particularly, to a feed plate configuration for directing crop material conveyed by the feederhouse in a linear path into a spiral path around the threshing and separating rotors.
Crop material is fed tangentially into the threshing cylinder of a conventional combine. Tangential feed is an easy and uncomplicated method of conveying crop material compared to the conveying of crop material longitudially into the end of an axial flow threshing and separating rotor. The feeding of a mat of crop material along a linear path by the feederhouse elevator and the subsequent dividing of the mat for feeding into a pair of transversly spaced threshing and separating rotors is particularly difficult.
The feederhouse elevator typically comprises a chain and slat conveyor operable within a hollow feederhouse structure to convey crop material collected by the attached combine header rearwardly into the threshing and separator mechanism. The feederhouse elevator in axial flow combines conveys the mat of crop material along a linear path to the infeed portion of one or more threshing and separating rotors. Each rotor includes an auger section operable to engage the mat of crop material delivered from the feederhouse elevator and convey it rearwardly into the threshing and separating sections of the rotor.
For an axial flow threshing and separating rotor to work properly, the amount of crop material must be conveyed along a spiral path around the circumference of the rotor to be subjected to a threshing action between the raspbars and the concave. Accordingly, the infeed geometry between the feederhouse elevator and the threshing and separating rotor, operable in conjunction with the auger thereof, is critical. Since the mat of crop material conveyed by the feederhouse elevator tends to hold inherently together, the separating of the amount of crop material into the two distinct spiral paths is even more difficult and highly dependent upon the infeed geometry of the rotor housing.
One type of infeed geometry specifically developed for axial flow combines having two transversely spaced threshing and separating rotors can be found in U.S. Pat. No. 4,291,709, granted on Sept. 29, 1981 to Steven J. Weber and E. W. Rowland-Hill. While this particular infeed geometry has been commercially successful, the guide plates provide dead spots where crop material can accumulate without entering the rotor chamber until a sufficient amount of crop material has been collected. When this happens, a slug of accumulated crop material enters the rotor chamber and may cause a noisy, inefficient operation when trying to thresh and separate the grain therefrom. Furthermore, the guide plates of this prior art infeed geometry do little to positively urge the crop material into a spiral path before entering the rotor chamber.